You can culture some species of fungi by simply “running” the mycelium on cardboard. Oyster (varieties of the genus Pluerotus), King Stropharia, Wood Blewitt, Nameko among others are amenable to this technique. It is a way of cloning a mushroom by creating the conditions for the mycellium to continue growing the cardboard. as a substrate cardboard is nutrient poor containing mostly cellulose and lignin. This gives the fungus an advantage over competitor organisms.
Ideally you can use the “stem butts” of the mushroom but you can also use mycellium growing on another substrate, such as, outdoor woodchip bed or fully colonised grain spawn. Most species that are adaptable to this technique a strong “basal rhizomorphs” visible root-like threads of mycelium (of course this is, in fact, hundreds if not thousands of hyphae banded together). The regenerative power of these species is such that the stem butt will revert to a mycelial vegetative stage if layered on the moist cardboard.
Once the cardboard is fully myceliated is can be used an an inoculum for pasteurised substrates or directly applied in natural methods of cultivation such as a woodchip bed or even log culture.
There are two simple methods; layering the cardboard in a plastic container; or making a cardboard “burrito”. Below we detail the Burrito technique but you can apply the layering method in a plastic container, just miss out the use of thicker card for the “wrap”.
- Hot water
- Large pot
- Plastic bag
- Sharp knife or scissors
- Chopping board
Method (Spawn Burrito):
- soak the cardboard overnight
- drain, pour boiling water over the cardboard in a pot, cover leave for 30 mins
- drain thoroughly and cool to below 36c
- pull the layers of cardbaod apart
- take a section of the thicker piece of the card (outer layer) this will be your wrap, put to one side
- you will now use the softer usuall inner layers, ideally corrugated. Be sure they are not dripping wet
- take stem butts, thinly slice them / cut them into small peices and layer them on the corrugated card. It easiest just to snip them up with scissors. Don’t worry if there is soil and debris, it doesn’t matter.
- repeat this layering until you have a number of layers that can be easily rolled.
- once you have rlled the inoculated layers, wrap it with the thicker section
- put the roll of card in a plastic bag, fold the top over once and staple (do not seal completely)
- Don’t forget to label the bag with the species and date
- incubate at around 20c for week or so; or if you are concerned about potential contamination start the incubationat a lower temperature
- once the mycellium has fully run throughout the card you can use it to inoculate a suitable growing substrate or expand further on cardboard.